An RCMP officer, who was among the first officers to respond to a horrific scene aboard a Greyhound bus, has reportedly taken his own life.

The family of 51-year-old Ken Barker says the recently retired colonel had been struggling with post-traumatic stress disorder — after two decades on the front line of violent crimes, the Toronto Star reports.

RCMP officers investigate a crime that occurred on a Greyhound bus where one man was beheaded by another, Thursday morning, July 31, 2008 about 18km west of Portage La Prairie, Man. By now, Vince Li was supposed to get out for some fresh air.The man who beheaded and cannibalized another man on a Greyhound bus in 2008 was given the privilege months ago. THE CANADIAN PRESS/John Woods

Tim McLean's father Tim shows the tattoo of his son to media as his wife Nadine looks on outside the Law Courts in Winnipeg on Thursday, March 5, 2009 after the verdict from the trial of Vince Li, the man who stabbed and beheaded McLean on a Greyhound Bus this past summer in Manitoba. Li was found to be not criminally responsible for killing Mclean. Li was found to be not criminally responsible for killing Mclean. THE CANADIAN PRESS/Winnipeg Free Press-Mike Aporius

An artist's drawing of Vince Li inside the courtroom in Winnipeg, Tuesday, March 3, 2009 for his second drgree murder trial. An agreed statement of facts read at the start of Li's second-degree murder trial Tuesday said he ignored horrified passengers as he attacked McLean and then mutilated the young man's body. THE CANADIAN PRESS/Tom Andrich

Carol deDelley (left), mother of Tim McLean, kisses her daughter Katie outside the Law Courts in Winnipeg on Thursday, March 5, 2009 after the verdict from the trial of Vince Li, the man who stabbed and beheaded McLean on a Greyhound Bus this past summer in Manitoba. Li was found to be not criminally responsible for killing Mclean. THE CANADIAN PRESS/John Woods